Vacuum molding apparatus



1386- 1966 A. R. TACCONE VACUUM MOLDING APPARATUS Filed Nov. 13, 1962 III] HHI ilHlH Hlii W [Win I NVENTOR. AR 77/0 R. 771cc om:

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United States Patent This invention relates to molding machines and, more particularly, to machines for making green sand molds.

In making green sand molds wherein patterns are used with deep cavities to form elongated projections on the mold, it is a problem to get the sand down into the bottom of the cavity to form a faithful reproduction of the shape of the part. Further, it is difiicult by present practices to remove from the cavity in the pattern and draw the finished elongated extension of sand formed on the mold without damaging the extension.

The present invention provides a means for impressing a vacuum on the bottom of deep cavities in patterns so that the sand will be induced to flow to the bottoms of the cavities. Further, a pressure can be alternately introduced into the cavity to help draw long extensions on the mold from the pattern. The invention has utility in any green sand molding application where it is necessary to move the sand into diflicult cavities and contours.

It is, accordingly, an object of the present invention to provide an improved combination molding machine and pattern.

Another object of the invention is to provide an improved pattern plate for sand molding.

A further object of the invention is to provide an improved pattern plate which is simple in construction, economical to manufacture, and simple and eflicient to use.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

The figure of drawing shows a molding machine partly in cross section to illustrate the invention.

Now with more particular reference to the drawing, a molding machine is shown having a base 11. The base 11 has a cylinder with a piston rod 12 thereon for moving the pattern plate, pattern, and loaded flask up into engagement with a head 13 to compress sand around the pattern. The head 13 may be a rigid member or it could be of the well known diaphragm type of molding head.

A flask support 14 is fixed to the piston rod 12 and it is made up of a rigid plate like member having upwardly extending sides thereon which define an enclosed chamber under a pattern plate 15. A suitable seal such as an O- ring is provided in an upwardly facing groove and the O-ring can be made to seal against the bottom of the pattern plate 15, thereby forming a sealed compartment under the pattern plate 15.

A flask 16 is of a conventional type having guide pins 20 which engage suitable openings in the pattern plate 15. Orifices 18 are provided through the pattern plate which communicate with the chamber in the flask support 14 and, at their upper ends, communicate with the bottoms of cavities 19 in the pattern. The source of vacuum and/or air under pressure is connected to a hose 21 through a channel 22.

In operation, a quantity of sand will be put in the flask 16 and the piston rod 12 will be extended to bring the flask 16 up so that the head 13 compresses the sand in the flask. As the pressure of the head 13 is applied to the sand, a vacuum will be applied through the hose 21 and channel 22 and orifices 18 to the bottoms of the cavities 19 in the pattern. This will induce the sand to flow down into the bottoms of the cavities and provide a faithful reproduction of the pattern which would not be possible if the sand were to be merely pushed by the head 13.

At the end of the molding cycle when the head 13 is withdrawn by lowering the piston rod 12 to move the head 13 away from the flask 16, a slight pressure can be applied to air in the hose 21 which will be impressed upon the bottom of the sand formed in the cavities 19. This will aid in withdrawing the finished mold from the pattern in a conventional manner Without damaging it.

The foregoing specification sets forth the invention in its preferred practical forms but it is understood that the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

A molding machine comprising a base,

means to support a pattern plate on said base,

means to support a flask on said pattern plate,

a pattern on said pattern plate,

said pattern having relatively deep cavities therein,

orifices in the bottoms of said cavities,

means connecting av source of vacuum to said orifices whereby sand is induced to flow to the bottoms of said cavities,

means above said pattern plate to pack molding sand around said pattern,

said means to support said pattern plate comprising a member on said base having upwardly extending members thereon defining a chamber,

said pattern plate resting on said upwardly extending members, sealing means providing a seal between said members and said pattern plate, said means connecting said source of vacuum comprising a channel through said member connected to said source of vacuum,

and means selectively connecting said source of vacuum and a source of air under pressure to said chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,475,935 12/ 1923 Coleman 2247 2,367,648 1/1945 Nichols 22192 2,951,260 9/ 1960 Harrison et al.

FOREIGN PATENTS 209,228 7/ 1957 Australia.

10,436 1884 Great Britain. 571,188 8/ 1945 Great Britain.

1. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, MICHAEL B. BRINDISI,

Examiners. E. MAR, Assistant Examiner. 

